It’s not your usual conversation with a fashion designer. “I put this dress in the wash last night because it was covered with food-y splodges,” says Samantha Cameron, peering down with a grimace at her immaculate emerald-green frock from her brand, Cefinn. “A bit of Vanish spray works wonders. Then I hung it up before I went to bed, and this morning I didn’t need to iron it or anything.”

At last. A label that factors in food-y splodges, not to mention those running-for-the-bus mornings with which most working women — especially those who, like Cameron, have children — are all too well acquainted.

The Camerons outside 10 Downing Street in 2016

BEN BIRCHALL/PA

However, this isn’t the 47-year-old’s only credential for heading a fashion brand aimed at delivering “clothes that work as hard as